Anemia In Pregnancy - Important Points To Know

Mild anemia is normal during pregnancy due to the increase in blood volume however, higher levels can be risky for the infant during later stages of the pregnancy. 

Give your Obstetrics and Gynecology preparation a boost with this informative blog post about Anemia in Pregnancy and all the important points you need to know about this topic for NEET PG exam preparation.  

Anemia in Pregnancy

Important information  MC cause of Anemia in pregnancy in India: Nutritional Anemia

Causes of Anemia

• 1. Decreased Production
  • Iron Deficiency Anemia
  • Megaloblastic Anemia
  • Folic Acid Deficiency Anemia
• 2.Increased Lysis
  • Hemolytic Anemia
  • Chronic Blood Loss

Definitions of Anemia

• WHO → Hb → < 11 gm%
• CDC → Hb → < 11 gm% or Hb → < 10.5 gm% in 3^rd trimester
• Mild → Hb → 10 -11 gm%
• Moderate → Hb → 7-10 gm%
• Severe → Hb → < 4 gm %

Iron Deficiency Anemia

Iron Requirement in Pregnancy

• 1000 mg elemental Iron [4-6 mg/ day x 280 = 1120 mg]: cannot be met diet alone
  • 500 mg - For Hb expansion
  • 300 mg - For fetus, placenta
  • 200 mg - Wasted

Management

• 100 mg / day elemental Iron Tab in Ⓝ pregnancy
• 200 mg / day elemental Iron in mild to moderate anemia
• Oral Iron supplementation forms like Fe Sulphate, Fe Ascorbate, Carbonyl iron are all better Absorbable forms 
• Every patient with anemia must be dewormed with MEBENDAZOLE (100 mg Tab BD x 3 Days)
• Injectable Preparations: The rate of increase of Hb with oral and injectable is same, thus the only indication for injectable iron use is Intolerance or Malabsorption. Stop oral Iron at the time of giving injectables as both use same gut receptors for absorption. Injectable forms available are 
  • Fe Dextran (IM/IV) 
  • Fe Sorbitol [IM]
  • Fe Sucrose (iv): No anaphylaxis (no test dose is given)
• Rate of rise of Hb with Oral & Injectable preparation is same [1 gm% Hb rise over 2 ½ - 3 wks]

Important information Requirement of Iron 2.21 x wt in kg x (Targeted Hb – Pt Hb) + 1000 mg (for stores) ≅ 200 mg / gm% Hb deficiency

• Requirement of Blood for Rx of Anemia in pregnancy
  • Indications: Hb: <7 gm% or patient is severely anemic later in pregnancy
  • Whole blood increases Hb by 0.8 - 0.9 gm%
  • Packed cells increase Hb by 0.8 - 0.9 gm %. This however gives lesser volume load than whole blood, thus preferred over whole blood.

Indices in Fe deficiency

• Serum Ferritin
  • 1st parameter to change
  • Ⓝ: 40-160 ng/ml
  • IDA: < 20 ng/ml
• Hb: ↓
• MCV: ↓
• MCH: ↓ 
• Serum total Iron: < 50 µg/dl
• Total Iron binding capacity: > 400 µg/dl
• Red cell distribution width (RDW): ↑

Thalassemia Indices

• RDW: Normal
• MCH: < 27 pg [Normal – 29 pg]
• Hb: Normal
• MCV/RBC: < 13 [Mentzer Index)
• On HPLC: HbA2 levels > 3.5
  • Do not overload patient with iron
• Peripheral smear of both IDA Thalassemia shows: Microcytic, Hypochromic, Anemia 

Megaloblastic Anemia

Causes

1. Folic Acid deficiency

• ↑ demand
• ↓ Supply
• Malabsorption
• Intestinal Sx or resection

2. Vit B₁₂ Deficiency

• ↓ Absorption: malabsorption syndromes
• ↓ Intrinsic factor
• Achlorhydria

Features 

• Slow onset 
• Hb ↓
• MCV: > 100 fL
• Requirement of folic acid: 0.4 to 0.5 mg/day
• Supplementation of Folic acid: 5 mg / day in Megaloblastic anemia
• Vitamin B₁₂ (Cobalamin) requirement is only met by non veg diet so Inj. cynocobalamin can be given in vegetarian females 

Nutritional Anemia / Dimorphic Anemia

• IDA (Microcytic hypochromic RBCs) + Megaloblastic Anemia (Hypersegmented neutrophils) 
• This is the most common type of anemia in pregnant women in India

To study anemia in pregnancy in detail, download the PrepLadder app and watch engaging video lectures or read through our comprehensive NEET PG study material. Also, find high-yield MCQs related to the topic for practice.